Thursday, April 26, 2012

Poison skies: Hanging over Japan is a Fukushima nuclear crisis that's far from over

Spent reactor fuel, containing roughly 85 times more long-lived
radioactivity than released at Chernobyl, still sits in pools vulnerable
to earthquakes.

More than a year after the Fukushima nuclear power disaster began, the
news media is just beginning to grasp that the dangers to Japan and the
rest of the world are far from over. After repeated warnings by former
senior Japanese officials, nuclear experts, and now a U.S. senator, it's
sinking in that the irradiated nuclear fuel stored in spent fuel pools
amidst the reactor ruins pose far greater dangers than the molten cores.
This is why:

Nearly all of the 10,893 spent fuel assemblies sit in pools
vulnerable to future earthquakes, with roughly 85 times more long-lived
radioactivity than released at Chernobyl

Several pools are 100
feet above the ground and are completely open to the atmosphere because
the reactor buildings were demolished by explosions. The pools could
possibly topple or collapse from structural damage coupled with another
powerful earthquake.

The loss of water exposing the spent fuel
will result in overheating and can cause melting and ignite its
zirconium metal cladding resulting in a fire that could deposit large
amounts of radioactive materials over hundreds, if not thousands of
miles.

This was not lost on Senator Ron Wyden (D-OR), who after
visiting the site on April 6, wrote to Japan's U.S. ambassador, Ichiro
Fujusaki, that "loss of containment in any of these pools... could
result an even larger release of radiation than the nuclear accident."

The urgency of the situation is underscored by the ongoing seismic
activity where 13 earthquakes of magnitude 4.0-5.7 have occurred off the
northeast coast of Japan between April 14 and 17. This has been the
norm since the first quake and tsunami hit the Dai-Ichi site on March 11
of last year. Larger quakes are expected closer to the power plant.

Spent nuclear fuel is extraordinarily radioactive and must be handled
with great care. In a matter of seconds, an unprotected person one foot
away from a single freshly removed spent fuel assembly would receive a
lethal dose of radiation within seconds. As one of the most dangerous
materials on the planet, spent reactor fuel requires permanent
geological isolation to protect humans for thousands of years.

It's been 26 years, since the Chernobyl reactor exploded and caught fire
releasing enormous amounts of radioactive debris -- seriously
contaminating areas over a thousand miles away. Chernobyl revealed the
folly of not having an extra barrier of thick concrete and steel
surrounding the reactor core that is required for modern plants, in the
U.S., Japan and elsewhere. The Fukushima Dai-Ichi accident revealed the
folly of operating several nuclear power plants in a high consequence
earthquake zone while storing huge amounts of highly radioactive spent
fuel in vulnerable pools, high above the ground.

What both accidents have in common is widespread environmental
contamination from cesium-137. With a half-life of 30, years, Cs-137
gives off penetrating radiation, as it decays and can remain dangerous
for hundreds of years. Once in the environment, it mimics potassium as
it accumulates in the food chain. When it enters the human body, about
75 percent lodges in muscle tissue, with, perhaps, the most important
muscle being the heart.

Last week, Tokyo Electric Power Company (TEPCO) revealed plans to remove
2,274 spent fuel assemblies from the damaged reactors that will
probably take at least a decade to accomplish. The first priority will
be removal of the contents in Pool No. 4. This pool is structurally
damaged and contains about 10 times more cesium-137 than released at
Chernobyl. Removal of SNF from the No. 4 reactor is optimistically
expected to begin at the end of 2013. A significant amount of
construction to remove debris and reinforce the structurally-damaged
reactor buildings, especially the fuel- handling areas, will be
required.

Also, it is not safe to keep 1,882 spent fuel assemblies containing ~57
million curies of long-lived radioactivity, including nearly 15 times
more cs-137 than released at Chernobyl in the elevated pools at reactors
5, 6, and 7, which did not experience meltdowns and explosions.

The main reason why there is so much spent fuel at the Da-Ichi site is
that the plan to send it off for nuclear recycling has collapsed. It was
supposed to go to the incomplete Rokkasho reprocessing plant, just
south of the Fukushima nuclear site, where plutonium would be extracted
as a fuel for "fast" reactors. This scheme is based on long discredited
assumptions that world uranium supplies would be rapidly exhausted and
that a new generation of "fast" reactors, which held the promise of
making more fuel than they use, would be needed. Over the past 20 years
the Rokkasho's costs have tripled along with 18 major delays. World
uranium supplies are far from depleted. Moreover, in November of last
year, Japan's "fast" reactor project at Monju was cancelled for cost and
safety reasons -- dealing a major blow to this whole scheme.

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The stark reality, if TEPCO's plan is realized, is that nearly all of
the spent fuel at the Da-Ichi containing some of the largest
concentrations of radioactivity on the planet will remain indefinitely
in vulnerable pools. TEPCO wants to store the spent fuel from the
damaged reactors in the common pool, and only to resort to dry, cask
storage when the common pool's capacity is exceeded. At this time, the
common pool is at 80 percent storage capacity and will require removal
of SNF to make room. TEPCO's plan is to minimize dry cask storage as
much as possible and to rely indefinitely on vulnerable pool storage.
Sen. Wyden finds that that TEPCO's plan for remediation "carries
extraordinary and continuing risk" and sensibly recommends that
"retrieval of spent fuel in existing on-site spent fuel pools to safer
storage... in dry casks should be a priority."

Despite the enormous destruction from the earthquake and tsunami, little
attention was paid to the fact that the nine dry spent fuel casks at
the Fukushima Da-Ichi site were unscathed. This is an important lesson
we cannot afford to ignore.

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